<% difficulty = 'difficulty' + @difficulty_index -%>
<tr id="<%= difficulty %>">
  <td>
    <label>Difficulty</label>
  </td>
  <td>
    <select name="<%= difficulty %>">
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
      <option value="4">4</option>
      <option value="5">5</option>
    </select>
  </td>
  <td>
    <%= link_to_remote "Remove",
      :url => {:action => 'remove_difficulty'},
      :update => difficulty %>
  </td>
</tr>